Charging apparatus



Feb. 28, 1950 M'. G. sHoz-:MAKER 2,499,170

CHARGING APPARATUS Filed oct. 1s, 1947 2 sheets-sheet 1 Feb. 28, 1950 M. G. sHoEMAKER CHARGING APPARATUS 2 Sheets-Sheet 2 Filed Oct. l5 1947 kN m um Patented Feb. 28, 1950 UNITED STATES PATENT GFFICE f f l2,499,170 v t v t cHAnGING APPARATUS i Malcolm G. Shoemaker, Doylestown, Pa., assigner to Philco Corporation, Philadelphia, Pa., a corporation of Pennsylvania Application October 15, 1947, Serial No. 780.082

(c1. sz- 115) 14 Claims.

The present invention relates to charging and, more particularly, is concerned with' a method of and apparatus for charging a refrigeration` system, or the like, with desired predetermined quantities of lubricant and refrigerant.

Known charging systems have been subject to difficulties and disadvantages, the nature of which will appear with more particularity from what follows, after an understanding is had of the functions required of such charging a-pparatus.

Firstly, and considering the invention as applied to the charging of refrigerator sealed units, the unit must rst be dehydrated, to remove any moisture therefrom in order to prevent the oc- V"currence of freezing at the expansion point of the flow regulating device. Dehydration, prior to the charging operation, has been accomplished in this art in several diierent ways and, for the purposes of the present invention, it is preferred to use the vacuum system of dehydration, at an elevated temperature. In order to insure that no moisture or non-condenslble gases enter the system after this dehydration and before charging, the unit is filled with gaa-preferably dichlorodifiuoromethane, to a pressure somewhat above atmospheric in order that, after reduction to room temperature, the pressure in the refrigerator system will be in the neighborhood of five pounds gauge, or above. This gas must be removed prior to the initiation of the charging cycle, to provide uniform conditions for chargent invention to provide charging apparatus of such a nature that its operation may be fully automatic, and in the use of which the operator need exercise a minimum of control during each ing and also to insure that the minimum amount of non-condensible gases remain in the unit or system.

Known charging apparatus is of the manually controlled and operated type and requires the manipulation of a relatively large number of valves, testing devices, and the like, during the charging operation. The constant attention of the operator is, of course, necessary. The known techniques are inherently of such a 4nature as to introduce manifold opportunity for errors on the part of the operator. which errors may result in an improperly or lnsufllciently charged system. For example, the operator may not allow sufieient time to reach the specified vacuum, and in this way the umts may prove faulty. Similarly, if the valves are not properly manipulated and the time of the manipulations is not closely controlled, variation in the charge may result. Not infrequently it has been found that units have been started in operation before sumcient lubrication is supplied to the compressor. thus damaging the bearing surfaces.

complete charging sequence.

, With more particularity, the invention is characterizedvby the provision of charging apparatus automatically operable to perform, inter alia, the following functions, comprising a preferred charging procedure which results in almost complete elimination of productionL rejects: (a) evacuate the charging apparatus; (b) test the refrigeration apparatus for leakage; (c) evacuate the refrigeration apparatus; (d) meter out predetermined quantities of constituents including lubricant and refrigerant; (e) charge the refrigeration apparatus with said constituents; (f) initiate operation of the refrigeration apparatus to draw any residual constituents from the charging apparatus and to insure proper lubrication prior to operation under full load; (g) terminate operation of the refrigeration system or unit and recondition the charging appartus to repeat the sequence when a succeeding refrigeration unit is associated with said charging apparatus.

The present invention also has as an object the provision of apparatus in which maintenance requirements are greatly reduced.

It is a further object to provide apparatus of the above character in which exact, predetermined amounts of refrigerant and lubricant are supplied to the refrigerating apparatus, regardless of changes in ambient temperature.

In another aspect of the present invention, it is an object to provide charging apparatus of such character as to obviate the necessity for utilizing constituent receptacles of precise volume.

In a method aspect, it is an object of the invention to charge refrigeration apparatus, and the like, by driving one charge constituent into the apparatus under the influence of the volatilization of anotherv constituent, and then operating the unit, whereby to withdraw any residual charge constituents into the apparatus at a predetermined low pressure.

The invention also has as an object the provision of apparatus of such a nature as materially to reduce both the charging time and the possibility of errors arising from the human element.

The manner in which the foregoing and other objects and advantages may best be realized will become clear from a consideration of the follownumbers followed by the subscript a.

ated devices, represented diagrammatically in Figure 1, and which circuits cooperate with and provide automatic operation of the charging components shown in Figure 1; and,

Figure 3 is a somewhat diagrammatic view of j a weight-responsive switching device preferably employed in the apparatus of the invention.

Now making more detailed reference to the drawings, and particularly to Figure 1 thereof, there is illustrated, by way of example, a refrigerator sealed unit of the type including an evaporator I0, a compressor Il and a condenser I2, which components are connected in series flow circuit by conduits including a capillary tube I3 and a suction line I4, which latter, in accordance with usual practice, has a portion I5 disposed in heat exchange relation with a section of the cap-v illary tube I3. Since the invention is not concerned with the refrigeration unit, per se, and since such units are well known in this art, further and more detailed description of this unit is not necessary herein.

The charging apparatus illustrated in Figure 1 includes three conduits or lines I6, I1 and I8. The conduit I6 leads to a vacuum pump,kshown diagrammatically at IBa, and which may be of any desired type; the conduit I 'I is connected to a receptacle I9, serving to deliver thereto fluid refrigerant from a supply vessel indicated at Ila; and the conduit I8 is in communication with the receptacle and it is through this latter conduit that lubricant is supplied to said receptacle from a source of lubricant shown at I8a.

The apparatus further includes a manometer 2l, employed during the evacuation process, and

, weighing apparatus diagrammatically indicated at 22 and through the agency of which the desired predetermined quantities of lubricant and refrigerant are established prior to charging of the system. While the quantities of refrigerant and lubricant are preferably determined in terms of weight, in the broader aspect of the present invention determination on a volumetric basis is also contemplated. The weighing apparatus, which may comprise any desired scale of proper range and sufficient accuracy, has associated therewith a switch device shown at 22a, which device cooperates in the automatic operation of the overall apparatus, as will clearly appear from what follows.

A number of valve devices are also included, these devices being shown at 23, 24, 25, 26, 21, 28 and 29. For the purposes of this invention, these valve devices may take any desired known form, and preferably are of solenoid actuated type, and the operation thereof is controlled by the automatic control circuits represented in Figure 1 and illustrated in detail in Figure 2. For the purposes of this portion of the description, it is suilicient to point out that these valves are actuated, respectively, by the solenoids and associated armatures which appear in the lower right hand portion of Figure 2 and bear corresponding reference These solenoids also appear adjacent the valves, in Figure 1, it being understood that the armature, physically, is within the valve casing. If desired, and within the purview of my invention, the valve devices 23 to 29, inclusive, may be actuated by suitable auxiliary mechanism, for example, by air under pressure, which auxiliary mechanism would, in turn, be responsive to the solenoid and amature assemblies shown at 23a to 29a.

A processing valve 30 is normally associated with the unit prior to its connection to the charging apparatus, and serves to connect said unit to a. terminal conduit 3l leading from the valve 23.

A number ofr pressure responsive switch devices are also employed, these being illustrated diagrammaticallyby the reference characters 32 to 35, inclusive. These pressure-responsive switches cooperate with portions of the automatic control circuits (represented at C in Figure 1 and shown in detail in Figure 2) in a manner which will be fully understood as the description proceeds.

An understanding of the overall apparatus will 'be facilitated by a brief initial description of the functioning of the components shown in Figure 1, after which such components and the functions thereof will be correlated with the sequence-controlling mechanism presently to be described.

A refrigeration apparatus or unit is connected to the charging mechanism bycoupling processing valve 30 tothe terminal extension 3|. The valve devices 23 to 29, inclusive, are of the normally closed type, and the automatic control circuits C serve to open said valve devices in a sequence determined by the several steps in the evacuation and charging procedure. Initially, the valves 24, 25, 26 and 29 are opened and ,theg charging board is evacuated, through line I6, .to a predetermined pressure as indicated by manometer 2|. Valve 24 is then closed and the reading of the manometer is noted to determine if any change in reading has occurred which would indicate leakage in the charging board conduits. Following this, valve 25, leading to the manometer, is closed and the processing valve 30 is opened, under which condition pressure switch 32 is subjected to the pressure in, thefunit and, if this pressure is within limits, the charging apparatus proceeds automatically. If this pressure is not found to be within predetermined limits, the charging is interrupted until it be determined whether or not leaks are present in either the charging apparatus or the unit.

l Valve 24 in the vacuum line is reopened at this time and evacuation of the'unit is initiated. Concurrently with the evacuation process, valves 21 and 28 are opened and refrigerant and lubricant are fed to the corresponding receptacles I9 and 20. In practice, the lubricant is rst introduced and, as will later appear, the switch 22a is automatically responsive to supply of a predetermined weight of lubricant to terminate supply thereof and to initiate supply of the refrigerant through conduit l1 and valve 21. The switch 22a is further responsive to supply of the desired quantity of refrigerant, by weight, to terminate supply of said refrigerant and thereafter to close the valve 24. and to open the valve 26 to accommodate delivery of the'charge constituents to the unit. Prior to such delivery, however, the unit processing tube 36 is pinched-off.

In order to force the lubricant into the unit, the valve 29, located between the receptacles I9 and 20, is opened momentarily thereby establishing communication between the receptacles and delivering the lubricant to the unit under pressure of the vaporizable refrigerant in receptacle I9. When all of the lubricant has been delivered to the unit, valve 29 is reopened and operation of the compressor is started by supplying power to the line oord 31 thereby drawing residual charging constituents into the unit until the pressure in the unit, and in those portions of the charging apparatus which are in communication therewith, have reached a predetermined rated pressure. In this way a uniform amount of charge is insured.

Closing of the processing valve 30 completes the procedure, after which the unit is disconnected from the terminal conduit or extension 3|.

In particular accordance with this invention, this novel charting procedure is effected in an automatic manner, as will now be described with especial reference to Figure 2.

The circuit shown in Figure 2 is the electrical system for operating the valves 23 to 29, inclusive, and energizing the power cord 31 of the motor compressor. In the interestof brevity in description, the operation oi' the circuit will be described concurrently with indication of the circuit components included.

Electric power, suitable for actuation of the control circuits and for energization of the compressor motor, is supplied to terminals L1 and La of the circuit. The operation of the circuit is such that the valves 23 to 29 are operated in the required predetermined order and in an established sequence, each step in the sequence being initiated upon completion of the previous step. In general. the system of Figure 2 consists of:

stepping relay 39; a second stepping relay or switch 40; a plurality of valve control switches; and certain magnetic actuators employed to actuate the valve control switches. Stepping relay 39 has two constactors or arms'll and 42, mechanically ganged as indicated in the drawing, arm 4| being used to complete the circuits necessary to step the relay to prepare it for the next operation, and arm 42 serving to actuate the valve control switches in the desired predetermined sequence. There is also provided an arm 43, which is manually adjustable and is used to preestablish the amount of refrigerant charge in accordance with the type of unit to be processed. Of the above-mentioned relays, those'shown at 45 to 5|, inclusive, are adapted to operate the valve control switches and thus to actuate the valves 23 to 29 through energization of the solenoid and armature assemblies 23a to 29a. Another relay 52 serves to reset the switch 39 to its initial position, as will presently appear, while a relay shown at 53 is used to provide an indication of the completion of certain operations, as well as to switch certain auxiliary circuits. The relay shown at 54 has its armature operatively associated with switch 4|! and is used in controlling the amount of refrigerant charge desired.

The various elements of` the apparatus are l shown in Figure 2 in the positions which they assume at the instant that the charging device has been reset and justbefore the relay 45 has been actuated to close the switches which it controls. Resetting ,is accomplished either automatically, by completion of the charging sequence, or manually-at am time in the cycle-by closing the contacts of a reset button shown at R, which returns the stepping switches to the nrst position. In this initial position, that is. when the charging apparatus is to be evacuated. power from line La is applied through arm 42 to relay 45 and thence to line Li. Relay 45,

upon actuation, closes switches 55, 56, 5l and 53.

in response to downward movement oi its arma- 5 ture and through a mechanical linkage, as is apparent from the drawing. Closing of these switches supplies energy to solenoids 24a, 26a and 29a. respectively. which in turn serve to open the valves 24, 26, and 29 and thus to connect the vacuum pump |611, the oil chamber or receptacle and the refrigerant chamber or receptacle I9 to the manifold 39. The vacuum pump Ita, which is represented diagrammatically and may be of any suitable type, then operates to evacuate manifold 38, and the lubricant and refrigerant receptacles 20 and I9. Preferably, the vacuum pump is of the continuously operating type, and is in communication with the charging apparatus and the system to be charged only when the valve 24 is open. However, as will be understood, the vacuum pump may be operated discontinuously, in which event operation thereof may be initiated manually. The evacuation is continued until the pressure in the manifold 39 reaches a predetermined value, at which value the pressure switch shown at 32 is set to operate. Pressure switch 32 then closes, energizing solenoid a and thus opening valve 25 which connects manometer 2| in the system, permitting checking of the pressure conditions. A pressure valve (represented in Figure 2 at 33) has a pair of contacts which are closed when the system has been evacuated to the required predetermined pressure. This serves to energize point P: of stepping switch 39, and thus ro condition the system for the next operation.

'Ihe purpose of this evacuation just describedV is to establish a ilxed initial pressure in a known volume, so that the remaining pressure in the unit being charged can be checked and-any leakage recognized. Along with the commencement of this iirst operation, the lamp 59 is lighted, concurrently with energization of solenoid 24a, and upon completion of the operation a lamp, shown at 88 in the right hand portion of Figure 2, is illuminated to indicate that the system is ready for further operation. The operator then closes starting switch 50, which operation opens a pair oi contacts 5|, through a mechanical linkage shown at 60a. This operation of switch 60 energizes arm 4| of switch 39 and'applies current through switch contacts 62 to rectier 63 and to the stepping winding 54 of switch 39. Stepping winding 54 then moves arm 4| from contact point P1 to contact point Pz. The closing of starting switch 50 also energizes" a timing motor, shown at 35, which is soconstructed that, upon being actuated, it operates a mechanical shaft 55a which closes switches 66 and 93, and opens o the switch shownat 61. I'he shaft then rotates one full revolution in a predetermined time, after which switches 56 and 93 are opened, switch 61 is closed. and rotation of the shaft 65a is stopped. The present invention is not concerned with the 05 timer, per se, and since such devices are now well known, further-and more detailed illustration and description are not necessary herein. However, attention is directed to the fact that this timer maybe of the type supplied by Eagle 70 Signal Co., and designated No. HA12A6-B242.

Concurrently with movement of arm 4| of switch 39 to point Pz, arm 42-being mechanically ganged with arm 4| moved from the point designated Q1 to point Q3. This movement energizes relay 49 which, upon` actuation, closes pressure in the system being equalized, and if itl is within limits, pressure switch 33 is closed rto energize point P2 on switch 39 as above described. This contact point P2, however, is only energized after the timer 65 has completed its cycle and has permitted contacts 61 to reclose. This provides a time delay insuring that, after the unit with its residual gas has been connected to the manifold, the vacuum pump |6a will have suilicient time to evacuate the system, this evacuation occurring as a result of switches 69 and 10, and their corresponding valves, having been closed concurrently with the above-mentioned closing of switch 68. Following this, stepping winding 64 actuates a hook member |96 and moves arms 4| and 42 of stepping relay 39 to the third position, that is, the position indicated by points P3 and Q3, and now to be described.

In the third position, in which the evacuation of the unit itself is checked, only switch 1| is closed, by the energization of relay 41. The vacuum pump |6a has been disconnected, but the unit remains connected to the manifold 38, by virtue of the actuation of valve 23. If the evacuation has been sufficient to bring the pressure in the unit within the range necessary to operate a pressure switch shown at 34 1n Figures 1 and 2, contact P3 will be energized and the switch 39 will be stepped to the fourth position.

The fourth position (points P4 and Q4) provides for delivery of the lubricant from vessel |8a to the receptacle 20. Switches 12, 13 and 'I4 are now closed, in response to the action of relay 48, thus opening valves 23 and 24 and 25. The unit under charge, the vacuum pump |6a and the manometer 2| are then connected to manifold 38. In addition, a switch shown at 15 is closed, energizing solenoid 28a through the upper closed contacts, 53a of relay 53, and connecting the lubricant supply tank through valve 28 to the lubricant receptacle '20. It will be recalled that the lubricant chamber has previously been evacuated and lubricant is therefore drawn into this chamber, with the manifold 38 and the unit held evacuatedvalve 26 being closed. A switch shown at 16 is also closed by the operation of relay 48, thus closing the circuit through the second set of normally closed contacts 53h of relay 53 and the stepping winding 11, to the line. This circuit energizes the above-mentioned scale switch 22a. As shown in Figure 1, the receptacles |9 and 28 are mechanically supported upon the scale 22 in such manner that the scale switch contacts 22a are closed as soon as a sumcient weight of lubricant has been drawn into the chamber 20. To this end, the receptacles are rigidly interconnected, as by means of the pipe shown extending therebetween, thus providing a unitary assembly which may bear against the scale 22. Vertical reciprocation of the assembly is accommodated by a pair of iiexible hose sections h-h, the solenoid 29a of course remaining in association with valve 29.

As clearly appears in Figure 3, the indicating arm of scale 22 is provided with a spider carrying a plurality of small magnets, shown at M1 to Ms, inclusive, `which are brought successively into registry with the switch contacts 22a, as the scale arm rotates clockwise. The scale switch is of known type, including one xed and one movable contact (22h and 22e, respectively), housed in a dust-resistant envelope. Any of the small magnets is effective to close contacts 22a, when brought into registry therewith. The magnet M1 is brought into such registry when the proper weight of lubricant has been delivered to the receptacle 20, the other magnets being utilized in preselection of the desired quantity of the refrigerant, in the manner explained hereinafter.

Closing of the contacts of scale switch 22a, by magnet M1, operates stepping winding 11 to move arm 44 from the ofi" position (N) to the rst position (Zi). This places relay 53 across the line, causing said relay to open those of its contacts which were previously closed. The upper contact 53a. now opened, was holding valve 28 open and, upon closing, valve 28 terminates the supply of lubricant to receptacle 20. 'I'he contacts 53o, are now opened, these being the contacts employed ,to energize the stepping winding 11. Upon opening of this set of contacts 53h, a ratchet hook, shown at 19, is released, and it engages the next tooth of the ratchet whereby to provide for subsequent operation of the arm 44.

Relay 53 carries an additional pair of normally open contacts shown at 80, which are closed upon actuation of the relay. As they close, a lamp 8| is lighted to indicate to the operator that the point in the cycle has been..

reached when he should pinch-off by-pass tube 36 on the sealed unit. Pinching-oi" may, of course, be accomplished automatically, if desired, thus obviating the necessity of actuating the start button as later described.

Up to this time, evacuation of the -unit took place through pipe 36, on the high side of the compressor, as well as through pipe l5, on the low side thereof. This was the case, in order thatA gas from the high side would not have to leak back through the valves or, alternatively, to traverse the capillary system before being evacuated. The pinching-off of pipe 36 is done to ensure that, during the next operation, when.

the lubricant is being delivered to the compressor, it will be delivered to the suction side and will not collect in the condenser I2. Upon operation of relay 53, the lower open contacts 53e are closed and a lamp, shown at 18, is lighted to indicate the fact that the oil has been weighed. Additionally, the line Ia is connected through these contacts which energizes point P4 on stepping switch 39 to move arms 4| and 42 to the fth position.

In the fifth position of stepping switch 39 (points P5 and Qs) relay 49 is energized which, as will now be understood, closes contacts 82, 83 and 84 with which'to connect the unit, the vacuum pump I6a and the manometer 2| to the manifold 38. In addition, switches shown at 85 and 86 are closed. Switch 85 places relay 54 and switch arm 43 in circuit. This circuit, however, is not yet completed, across the line, since arm 44 has not yet reached a contact point which will permit the circuit to be closed through arm 43, relay 54 and contact 85. Arm 43 is manually adjusted, prior to the charging operation, and may rest on any one of the several contacty points shown. Each of these contact 9 points corresponds to a different predetermined weight onthe scale shown in Figure 3, and the contact point appropriate to the type of unit being charged is manually selected before charging commences. The scale switch 22a is so included in the circuit that, assuming for example that the amount of refrigerant desired corresponds to the illustrated position of arm 43, the indicating hand of the scale will rotate clockwise until magnet M is brought into registry with the scale switch contacts 22h and 22e.

Closing of switch 95 additionally energized the upper set of normally closedcontacts 54a of relay 54, and in this way opened the valve 21 through operation of solenoid 21a. The refrigerant, under pressure in line I1, is thus connected to the previously evacuated receptacle I9. As the refrigerant lls the receptacle, the scale arm is rotated clockwise and the indicating hand of the scale also rotates clockwise until the next of the magnets associated with the scale arm is brought into registry withthe scale switch contacts 22h and 22e. The resultant closing, of scale switch 22a, under those circumstances, completes the circuit through switch 86, contacts 54h and stepping winding 11, thereby causing hook 19 to rotate switch arm 44 one step. Arm 44 had previously been resting on contact point Z1 as a result of the previous operations described above, and is thus moved to con tact u point Z2. For purposes of explanation, it is assumed that switch arm 43 had been manually set to a position other than that connected to contact point Z2. Under these circumstances, the closure of switch 22a, by passage of the magnet,

, .isineffective to produce any result other than causing arm 44 to step up one more position.

'I'his series of operations, just described, takes place each time one of the magnets M2 to Ma passes switch contacts 22h and 22o until the proper predetermined Weight of refrigerant is delivered to receptacle |9, that is, until the magnet M5, which corresponds in number with the manually adjusted position of arm 43, is reached, and the arm 44 comes to rest on a contact point connected to arm 43 (position Z5, as illustrated). When this point has been reached, the circuit is closed from line L2 through contact 85, relay 54, arm 43, arm 44 and back to the line L1. Relay 54 then operates to transfer the contacts controlled thereby, thus preventing further operation ofthe stepping switch 11, and closing valve 21 to stop the further ow of refrigerant. As the ow of refrigerant ceases, relay 54 closes its normally open contact 54e thereby lighting a pilot lamp 81 to indicate that the refrigerant has been weighed. As shown in Figure 2, each of the relays 24a, 21a and 28a, and 45, 41, 59 and 5|, is provided with a lamp adapted to indicate the energization of the associated relay. While these lamps assist the operator in determining the condition of the charging apparatus, detailed consideration of the use thereof is not necessary to a full understanding of the present invention. The normally open Y contact 54e, when closed, energizes point P5 on switch 39 causing it-to step to the sixt position.

The operation which takes place with the apparatus in the six position is as follows: Switches 68, 69 and .19 are closed, due to the energization of relay 46, thereby connecting the unit, the vacuum pump and the manometer to the manifold 38. When the evacuation is suiliciently complete, the pressure switch 33 is closed and the indicatinglamp 88 is illuminated. In this way the operator is advised that he may push button 60 to l 0 initiate further automatic operation of the cycle. This button is actuated after he has pinched oil.' the by-pass pipe 36, in response to illumination of the pinch-oi! lamp l 8|, as above indicated. When the apparatus is'in this position and the operator so actuates start button 69, he closes the circuit through the arm 4| and through stepping winding .64 thereby moving the relay 39 to the next position, that is, to the position indicated by points P1 and Qc. At this time, starting switch 69 also closes the circuit to the above-mentioned Y timer 65.

In the seventh position, arms 4| and 42 are on their seventh set of contact points (P7, Q1) and the charging of the unit with lubricant and re*- frigerant is initiated. Relay 59 is energized,

which closes switches 89, 99 and 9| Switch 89 then starts operation of timing motor 92 and switches 90 and 9| actuate valves 23 and 28 connecting the unit and the oil receptacle 29 to the manifold. YTimer 65, operation of which has previously been started by manipulation of starting switch 60, closes switches 66 and 93 and holds them closed forone complete cycle of operation of timer 65. For convenience in illustrating the electrical circuits, the timer-controlled switches are shown as physically removed from the timer motors, appropriate mechanical linkages being illustrated by, means of the conventional dashed line representation. The contacts of switch 66 supply current to timer 65, after the starting button 60 is released. The contacts of switch 93 energize solenoid 29a which opens the valve 29, momentarily, between the Freon. chamber I9 and the oil chamber 20. vThe manifold--having previously been evacuatedis now connected to the lubricant receptacle 20 and to the receptacle I9, which latter contains refrigerant under pressure. The refrigerant pressure drives the lubricant through the manifold and the processing valve 39,

- into the unit being charged. Because the by-pass pipe 36 has been pinched-off,-all of the oil thus delivered to the unit is driven into the suction side of the compressor where it is available to lubricate the compressor.

It should be noted that timer 92 operates somewhat dilerently than does timer 65. Timer 92 closes the switch contacts 94 momentarily after it has completed its timing cycle. This timing cycle is made long enough to assure that sufficient oil to lubricate the compressor has been injected into the unit. When switch 94 is closed the stepping winding is energized, through arms 4|, and stepping relay 39 is advanced to the eighth contact position. Again, and as indicated with respect to timer 65, timer 92 is of known type, and further and more detailed description thereof is not necessary to an understanding of this invention. In this instance also, a timer supplied by the Eagle Signal Co. (No. HAMAS-B212) may be used.

In the eighth position, in which operation oi' the compressor is initiated and the residual refrigerant is drawn into the unit, relay 5| is energized by arm 42, and switches 95, 96, 91 and 98 are closed. As a result, valves 23, 26 and 29 are held open so that the receptacle I9, with its remaining refrigerant under pressure, is connected through the manifold 38 to the unit. At the same time, power cord 31 of the motor compressor is energized through a switch 98 and plug 31a, in series with an automatic overload circuit breaker 31b. The motor compressor now commences to run and is lubricated by the oil previously supplied during the seventh operay Y 11 tion. The operation of the motor compressor is such as to draw in any lubricant or refrigerant i remaining in the receptacles and in the manifold 38, and drives therefrigerant into the condenser |2, where'it is compressedagainst the resistance of capillary tube I3. In this way the high pressure side of the unit will contain refrigerant under the normal high pressure and mined value, the pressure switch 35 closes and l5 pended claims.

energizes stepping winding 64 to operate steppingy relay 39. This drives the stepping relay arms Il and 42 to the ninth position, designated P9 and Q9 in Figure 2.

As soon as the arms arrive in the ninth position, relay 52 is energized. Energization of relay 52 closes the contacts of switches 99, |00 and |0|, and opens those of switch 52. Another switch, appearing at |02, is closed in all positions of stepping relay 39 with the exception of the iirst position thereof, when it is opened by a cam appearing at |03. Relay 52 was initially actuated by arm l2 when it reached the ninth position and, while arm l2 is being returned to its initial position, relay 52 is held energized through conl 30 tems, receptacle means, means adapted to suptacts |02 and |00. Contacts |0| now energize relay winding |04 thus operating a release arm |05 to release the pawl |06 from stepping relay 39. Stepping relay 39 is then returned to its initial position, under the influence of a spring (not shown). In returning to its initial position, arm 4| passes over various contact points which may be energized and this operation might actuate stepping winding 6l. To prevent this, switch 62 is held open while relav 52 is energized. It is unnecessary to provide additional, normally closed contacts in series with arm I2, as the various relays and contacts energized by this arm in returning to its initial position aresufficiently slow-acting to be substantially unaffected'by this operation. Switch 99 was also closed by relay 52, thus energizing release windings |01, |08 and |09. to restore selector l0, relay 53 and relay 5l to initial position. Contacts on the' shaft of stepping switch I0 are held open by a cam i in the initial position (N) of arm Il. They are closed in all other positions of arm 44 including the position' at the termination of the cycle. Relay 52 is deenergized when arm 4| returns to normal, as a result of the Aopening of switch |02. Along with such deenergization, windings |01, |00 and |09 are deenergized.

It will now be evident that the charging of the unit is complete, and that the charge of lubricant and refrigerant is in that portion of the unit which it would occupy. after the unit had been turned oi by the usual thermostat. All of the solenoid valves are closed, including valve 23 connecting the unit to the manifold. The operator now closes valve 30 to seal the unit, which may then be disconnected from the charging board by disconnecting it from pipe 3|, and

the charging apparatus is now ready to repeat the above-described sequence of operations, in conjunction with another refrigeration unit.

From the foregoing description, it will be understood that the present invention provides for charging of refrigeration apparatus, and the like, in a rapid, accurate and automatic manner, and that the system is such that the operator invention is susceptible ot changes and modifications without departing from the essential spirit thereof. For example, inthe broader aspect, it is within the vpurview of the invention to modify the apparatus in such manner that l0 other instrumentalities may be employed in place 'of the electromechanical control system shown and described. However, it will be understood that such changes and modifications are contem` plate'd as may come within the terms of the ap- I claim:

1. In apparatus for charging refrigeration systems, receptacle means, means adapted to supply to said receptacle means charge constituents,

means for measuring the quantity of constituents supplies, apparatus automatically responsive to supply of predetermined quantities of said constituents to provide for delivery of said constituents to an associated system being charged,

and instrumentalities adapted to initiate operation of the associated system to draw residual portions of said constituents from the receptacle means and into the system.

2. In apparatus for charging refrigeration sysply to said receptacle means-in a predetermined sequence-twd different Acharge constituents, means for measuring the quantity of constituents supplied, electromechanical apparatus controlled by said measuring means and automat.

cally responsive to supply of a predetermined quantity of one constituent to terminate supply of said one constituent and to initiate supply of the other constituent, said electromechanical 40 apparatus being responsive to supply of a prel determined quantity of the said other constituent to terminate supply of the said other con-v stituent and adapted to establish communication between said receptacle means and an associated system being charged, whereby to provide associated System.

3. In apparatus for charging refrigeration systems, receptacle means, means adapted to supply to said receptaclemeans-in a predetermined sequence-two diiferent charge constituents,

65 means for measuring the quantity of constituents supplied, apparatus controlled by said measuring means and automatically responsive to supply of a predetermined quantity of one constitu- `ent to terminate supply of said one constituent and to initiate supply of the other constituent,

said last-mentioned apparatus being responsive to supply of a predetermined quantity of the said other constituent to terminate supply of the said other constituent and to` establish communication between said receptacle means and the system, whereby to provide for delivery of said constituents to an associated system being charged, means adapted to initiate operation of the system to draw residual portions of said constituents from the receptacle means, and pressure-responsive switch means effective to terminate operation of such system when the pressure therein has reached a predetermined value.

4. In apparatus for charging refrigeration systems. a pair oi' receptacles, means adapted to Y consisting of lubricant and vaporizable fluid refrigerant, the construction and arrangement being such that each constituent is supplied exclusively to one of said receptacles. and electromechanical means responsive to completion of the supply ofpredetermined quantities oi' said constituents and adapted to establish vcommunication between said receptacles and between the lubricant receptacle and an associated system being charged, the establishment of such communication serving also to decrease the pressure in the receptacle containing said vaporizable fluid refrigerant thus permitting volatilization of said refrigerant and providing for delivery oi' said lubricant to the system under the influence of the pressure created by volatilization of the refrigerant.

5. Charging apparatus in accordance with claim 4, further characterized in that said electromechanical means includes valve structure automatically operable to establish the said communication between said receptacles and to maintain said communication for a predetermined short period of time.

6. In apparatus for charging refrigeration systems, a pair of receptacles, means adapted to supply to said receptacles-in predetermined se-r quence-charge constituents consisting of lubricant and vapqrizable uid refrigerant, the construction and arrangement -being such that each constituent is supplied exclusively to one of said receptacles,rand means responsive to supply of a predetermined quantity of the last constituent supplied and adapted to establish communication between'said receptacles and between the Y each constituent is supply to said receptacles-in predetermined sequence-charge constituents consisting of lubricant and vaporizable iluid refrigerant. the construction and arrangement being such that each constituent is supplied exclusively to one of said receptacles, and means responsive to supply of a predetermined quantity of one constituent to terminate supply of said one constituent and to initiate supply of the other constituent, said means further being responsive to supply of a predetermined quantity of the said other constituent and adapted to terminate supply thereof and to establish communication between said receptacles and between the lubricant receptacle and an associated system being charged, the establishment of such communication serving also to decrease the pressure in the receptacle containing said vaporizable fluid refrigerant thus permitting volatilization of said refrigerant and providing for delivery of said lubricant to the systemunder the influence of the pressure created by volatilization of the refrigerant.

8. In apparatus for charging refrigeration systems, a pair of receptacles, means adapted to supply to said receptacles-An a predetermined sequence-charge constituents consisting of lubricant and vaporizable fluid refrigerant, the construction and arrangement being such that supplied exclusively to one of said receptacles, and electromechanical means responsive to. supply of a predetermined quantity of the last constituent supplied and including valve structure operable to establish communication between said receptacles for a short period of time and concurrently therewith to establish' communication 4between'the lubricant receptacle and an associated lsystem being charged, the establishment of such communication serving also to decrease the pressure in the receptacle containing said vaporizable fluid refrigerant thus permitting volatilization oi' said refrigerant and providing for delivery of said lubricant to the system under the inuence of the pressure created by volatilization oi' the refrigerant.

9. Charging apparatus in accordance with claim 8, and further including electrical circuits adapted to initiate operation of the associated system after the said introduction of the lubricant, whereby to draw residual vaporizable refrigerant from said receptacles and into the associated system. v

10. Charging apparatus in accordance with claim 9, and further including pressure-responsive switch means adapted to terminate the said operation of the refrigeration system when a predetermined low pressure has been reached within the system.

11. In apparatus for charging refrigeration systems, receptacle means, means eiIective to evacuate said receptacle means, means responsiver'to completion of said evacuation to initiate evacuation of an associated system being charged, means adapted to supply to said receptacle means -in a predetermined sequence-two ditl'erent charge constituents, means for measuring the --quantity of constituents supplied, electromechanical apparatus controlled by said measuring lmeans and including switch means automatically responsive to supply of a predetermined quantity of one constituent to terminate supply of said one constituent and to initiate supply of the other constituent, said switch means further being responsive to supply of a predetermined quantity of the said other constituent to terminate supply of the said other constituent and thereafter to establish communication between said receptacle means and an associated system being charged, means adapted to initiate operation of the system to draw residual portions of said constituents from the receptacle means and into the associated system, and pressure-responsive switch means adapted to terminate operation of the system when the pressure therein has reached a predetermined value.

12. In apparatus for charging refrigeration systems, a, manifold to which may be coupled an associated system to be charged, receptacle means adapted to be placed in communication with said manifold, a source of lubricant, a source of refrigerant, each of said sources adapted to be placed in communication with said receptacle means, and apparatus including valve means automatically operable to establish communication between one of said sources and said receptacle means and thereafter to establish communication between the other of said sources and said receptacle means, said apparatus and valve means further being responsive to supply of predetermined quantities of said constituents to said receptacle means to terminate supply of said constituents to said receptacle means and to establish communication between said receptacle vamarre delivery of said constituents tothe associated system. .Y

13. A- construction in accordance'with claim 12, in which said last-mentioned apparatus includes means for weighing the constituents supplied,

said construction being further characterized in that supply of said constituents is under the control of said weighing means and communication between said receptacle means and saidmanifold is established in response to supply of predetermined constituent weights to said receptacles.

14. In apparatus for charging refrigeration systems, a manifold to which may be coupled an associated system to be charged, a pair of receptacles each adapted to be placed in communication with said manifold, a source of lubrica-nt, a source of vaporizable iiuid refrigerant, means for lestablishing communication between said sources and said receptacles whereby tol deliver the lubricant andrefrigerant to corresponding separate receptacles, and apparatus including valve means responsive to supply of predetermined quantities oi' said constituents to said receptacles to terminatel said last-mentioned t 16 t communication and to establish communication between-'said'receptacles and'between the lubricant receptacle and said manifold,tthe yestablishment of such comin unicationv servingl also vto decreasethe pressure' in the receptacle .containing said vaporizable iluid refrigerant thus permitting volatilization of saidl refrigerant and pro- `viding for"delivery of'said lubricant to the associated system under'the iniluence of the pressure'created by volatilization of the refrigerant.

` ,MALCOLM G. SHOEMAKER.

lREFERENCES CITED A The followingfrefer ,ces are of record the 

